Method and apparatus for applying bonding material to component leads

Abstract

A controlled amount of a solder is applied to the tip (18) of each lead (14) of a multi-lead component (10) by first placing a solder sphere (30) in each of a plurality of cavities (24) arranged in a baseplate (22) in the same pattern as the tips of the leads. Thereafter, the tips of the leads of the component are placed in contact with the solder spheres while, at the same time, at least a pair of leads are each engaged by a separate one of a pair of alignment pins (32) rising upwardly from the baseplate. The alignment pins serve to constrain the lateral movement of the component, thereby maintaining the leads thereof in alignment with the solder spheres when the solder spheres are reflowed to bond to the tips of the leads.

What is claimed is: 
     
       1. A method of fabricating an article comprising the steps of: applying a controlled amount of a bonding material to the conductors on a component by placing each conductor in contact with bonding material seated in each of a set of cavities in a plate arranged in the same pattern as the conductors and then reflowing the bonding material; and thereafter   bonding each conductor to a substrate, characterized in that:   each conductor is a lead having a tip placed in contact with the bonding material in each cavity; and   at least each of a pair of said leads is engaged with a separate one of a pair of alignment pins, respectively, each rising upwardly from the plate adjacent to a pair of cavities, so that the alignment pins constrain the lateral movement of the component to maintain said leads in alignment with said bonding material during the reflow thereof.   
     
     
       2. The method according to claim 1, characterized in that each of said pair of alignment pins engages said component after the component has descended a predetermined distance to limit the extent to which said leads sink into said bonding material during the reflow thereof. 
     
     
       3. The method according to claim 1, characterized in that each of said pair of leads is engaged by a separate one of said pair of alignment pins by placing said tips of the leads in contact with said bonding material such that each of a pair of said leads straddles each alignment pin. 
     
     
       4. The method according to claim 1, characterized in that: each of said pair of leads of said component is engaged by each of said pair of alignment pins by placing the tips of said leads in contact with the bonding material such that each of said alignment pins engages a corner of each of said pair of leads.   
     
     
       5. The method according to claim 1, characterized in that the bonding material preferentially bonds to each lead rather than to the base plate, and that following the reflow of said bonding material, said component is separated from the baseplate. 
     
     
       6. The method according to claim 1, characterized in that prior to placing the tips of the leads in contact with the bonding material seated in the cavities, a template is placed on said baseplate so that the pattern of cavities lies inside a central opening in the template and the alignment pins are each received in a corresponding notch in the periphery of the template central opening, and thereafter, the component is placed within the central opening of the template which aids in aligning the tips of the leads with the bonding material in each cavity. 
     
     
       7. A method of fabricating an article comprising the steps of: applying a controlled amount of a solder to the tip of each conductor of a component by placing each conductor in contact with each of a plurality of solder spheres seated in each of a plurality of cavities in a plate arranged in the same pattern as the conductor and reflowing the solder spheres; and thereafter   solder bonding each said lead of said component to a circuit board, characterized in that:   each conductor is a lead whose tip is placed in contact with the solder sphere in each cavity;   prior to placing the tips of the leads in contact with the solder spheres, a template, having a central opening with notches in the periphery thereof, is placed on the baseplate such that the pattern of cavities lies within the template central opening and each of a plurality of alignment pins rising upwardly from the base plate adjacent to the cavities seats in a notch in the periphery of the central opening, the template aiding in the alignment of the tips of the leads with the solder spheres; and   at least each of a pair of said leads is engaged with a separate one of a pair of the alignment pins when the lead tips are placed in contact with the solder spheres, so that the alignment pins constrain the lateral movement of said component, thereby maintaining said leads in alignment with the solder spheres during the reflow thereof.   
     
     
       8. The method according to claim 7, characterized in that each of said pair of alignment pins engages the component after the component has descended a predetermined distance to limit the extent to which said leads sink into said solder spheres during the reflow thereof. 
     
     
       9. The method according to claim 7, characterized in that the bonding material preferentially bonds to each lead rather than to the base plate, and that following the reflow of said bonding matrial, said component is separated from the baseplate. 
     
     
       10. The method according to claim 7, characterized in that each of said leads is engaged by each of said pair of alignment pins by placing said tips of the leads in contact with said solder spheres such that each of a pair of leads straddles each said alignment pin. 
     
     
       11. The method according to claim 7, characterized in that: each of said pair of leads of said component is engaged by each of said pair of alignment pins by placing the tips of said leads in contact with said solder spheres such that a corner of each lead is captured by each of said alignment pins.   
     
     
       12. Apparatus for applying a controlled amount of bonding material to the tip of at least one lead of a multi-lead component comprising: a baseplate having a plurality of cavities in a major surface thereof arranged in the same pattern as that of the leads for holding a quantity of bonding material therein, characterized in that each of a plurality of alignment pins rises upwardly from the baseplate adjacent to a pair of the cavities to engage each of a plurality of leads of said component upon the placement of the tips of the leads in contact with the bonding material in a separate one of the cavities in said baseplate to constrain the lateral movement of said component.   
     
     
       13. The apparatus according to claim 12, characterized in that each said alignment pin includes means thereon to engage said component to limit the distance which each said lead sinks into said bonding material during the reflow thereof. 
     
     
       14. The apparatus according to claim 12, characterized in that said apparatus further includes a template having a central opening therein sized to receive the component, the central opening also having a plurality of notches in the periphery thereof to accommodate each of the alignment pins when the template is placed in intimate contact with the baseplate so that the central opening in said template is in registration with said cavities. 
     
     
       15. A method of repairing a circuit board having at least one defective component which has each of a plurality of leads bonded to a separate one of a plurality of metallized areas on the surface of the circuit board comprising the steps of: removing the defective component from the circuit board; and   bonding each of the leads of a replacement component to the pads on the circuit board previously bonded to the defective component wherein each lead of said replacement component has a controlled amount of bonding material applied thereto by a process including the steps of:   applying a controlled amount of bonding material to the tips of each of the leads of the replacement component by placing the tips of the leads in contact with bonding material seated in each of a plurality of cavities in a plate arranged the same as the pattern of the leads; and   reflowing the bonding material, characterized in that each of a pair of leads is engaged by a separate one of a pair of alignment pins, each rising upwardly from the plate, when the tips of the leads are placed in contact with the bonding material so that said alignment pins constrain the lateral movement of said component to maintain said tips of said leads in alignment with the bonding material during the reflow thereof.   
     
     
       16. A method for fabricating an article comprising the steps of: applying a controlled amount of bonding material to the conductors on a component by placing each conductor in contact with bonding material seated in each of a set of cavities in a plate arranged in the same pattern as the conductors;   then reflowing the bond material; and thereafter   bonding each conductor to a substrate, characterized in that:   a relative motion is imparted between the conductors on the component and the plate to bring the conductors into contact with the bonding material while simultaneously constraining the lateral movement of the conductors with alignment pins affixed to the plate so the conductors are maintained in alignment with the bonding material.